Pre-Algebra - Polynomials

A polynomial refers to more than one monomial or, in other words, it refers to two or more monomial numbers that are linked together through an equation by an addition sign (+), subtraction sign (-) or a multiplication sign (x). “Poly” refers to “many.” For example: 2x² + 6x².

This example has two monomials that are linked by an addition sign (+) making it a polynomial.

Although this example is a polynomial, generally when you have only two monomials linked, it is called a binomial.

When you have three monomials linked, i.e., 4x⁷ + 5x⁶ - 9x⁵ then you have what is referred to as a trinomial. Anything beyond three linked monomials is referred to as a polynomial even though both the binomial and the trinomial can also be referred to as polynomials. (Note: When you have a polynomial, the degree of the polynomial is the highest exponent number so in this polynomial the highest exponent is “7” making the degree of the entire polynomial “7”.)

When writing out polynomials, they are generally written in the descending order of exponents. For example, let’s relook at the above polynomial. The exponents are 7, 6 and 5 and are written in a descending order. Whenever you have a number such as 3x, the x is understood to have an exponent of “¹”. So if we were to add the 3x to our polynomial it would be added in descending order to read: 4x⁷ + 5x⁶ - 9x⁵ + 3x.

What are “like” terms? Like terms are when you have the same variable and/or the same exponents. For example: 4x - 6x. Here the variable “x” is the same so then you can easily work the coefficients, i.e., “4” and “6” or 4 - 6 = -2. They each have the same variable “x” so the problem is worked: 4x - 6x = 4 - 6 = -2x.

When working a problem with like terms, once you have collected your “like” terms, you are done with the problem. For example, take the polynomial: 5x³ - 2x³ + 10. This would be worked out as: 5x³ - 2x³ + 10 = 5 - 2 = 3. As the same variable is x³ then the problem would proceed to be written as: 5x³ - 2x³ + 10 = 5 - 2 = 3x³ + 10. Since 3x³ and 10 are NOT like numbers, you are done working the problem so the sum or answer of this polynomial is 3x³ + 10.